Fruit knife



FIG. 1 is a top plan view of a fruit knife showing my new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a left side elevation view thereof; and

FIG. 6 is a right side elevation view thereof. 

The ornamental design for a fruit knife, substantially as shown and described. 